Ophthalmic-lens blank.



H. c. MIELKE. OPHTHALMIC LENS BLANK.

APPLICATION FILED DEQZE, I9l7.

PatentPd N0". 19, L918.

2 SHEETS- SHEET l- FUEL,

FHEQE H. 0. MIELKE.

OPHTHALMIC LENS BLANK.

APPLICATION FILED DEC-26.1917- Patented Nov. 19, 1918.

2 SHEETS-SHEET 2.

FREDDIE,

FEEDS R Q T N E V m glass into a mold.

Y C. MIELKE, OF ROCHESTER, NEW YORK.

I OPHTHALMIC-LENS BLANK.

specification of Letters Patent. Patented Nov, 19,1918.

Application filed December26, 1917. I Serial No. 208,775.

To all whom it may concern:

Be it known that I, HENRY CHARLES MIELKE, a citizen of the United States, and resident of Rochester, in the county of Monroe and State of New York, haveinvented certain new and useful Improvements in Ophthalmic-Lens Blanks, of which the following is a specification.

The present invention relates to a blank for forming a plurality of ophthalmic lenses, an object of this invention being to provide for reducing the cost of producing a lens of the type mentioned.

To this and other ends the invention consists of certain parts and combinations of parts, all of which will be hereinafter described, the novel in the appended claims.

In the drawings Figure 1 is a sectional view through a cylinder showingthe first steps of the present method;

Fig. 2 is an end shown in Fig; 1; I

Fig. 3 shows, in section, the cylinder divided into three segments or rings;

Fig. 4 is a side viewof a forming wheel on which the cylinder segments or rings are molded;

Fig. 5 is an axial section-through such forming wheel; Fig. 6 shows, in section, the manner of forming "the blank on the forming wheel from thering segments shown in Fi 3;

Fig. 7 is a perspective .view of't e completed ring blank before grinding and polishing;

Fig. 8 is a ground and p which the individual from the' blank;

Fig. 9 is a face view of one of the individual lens blanks; and

Fig. 10 isa sectional view through the individual lens blank shown :in Fig. 9.

view of the cylinder perspective view of the blank lenses may be formed According to this invention molten glass is formed into a. hollow cylinder, as shown in Figs. 1 and 2, preferably After molding, the cyl'-' inder is annealed. The thickness of the wall of the cylinder varies with the focal power of the lenses, being, millimeters. The outside diameter of the hollow glass cylinder depends on the base curve of the lenses, being, say, for instance,

features being pointed out lished showing the manner in by blowing the say, for instance, three 116 millimeters. The cylinder may be of any suitable length, say, for instance, 141 millimeters, which permits the cutting of three blank rings each having a surface width of 47 millimeters.

Each ring after being cut from the cylinder is heated to a plastic state, and is then applied to the mold wheel or former shown in Figs. 4 and 5. This mold wheel or former comprises, in this instance, three segments 3, each of which'is supported by an arm or spoke 4 extending from a hub segment 5. The segments 5 fit on a spindle 6, being held against a shoulder 7 on said spindle by a tapered nut 8 adjustable on a screw threaded portion 9 on the hub segments 5. This nut permits the withdrawal of the spindle L from the hub sections 5, so that the mold former 3. Theflat or have any desirable curve transversely of its plane of rotation, so that a toric or spherical curve may be rovided on the inner face of the ring. The form of the face 11 of the roller 10 may be varied to produce a flat surface or any desired toric or spherical curve on the outer face of the ring. Owing to the fact that the sections spaced from each other, openings are provided in which portions of the plastic ring may be forced during rolling, so as to prevent-the slipping of the plastic ring on the mold wheel or former. The ring blank, after being shaped to correspond to the curved face of the mold wheel or former, and also to the curve of the roller, is removed from the mold wheel and annealed. The completed blank before grinding and polishing is shown in Fig. 7 at 13, the internal transverse ribs on the ring indicating those portions which enter between the segments of the mold wheel. The ring may now be mounted upon a suitable holder and ground and polished to the curvature desired.

Assuming when both sides have been completed that the convex side is a toric' surface having a base curve cf 6 dioptric power,

3 are slightly --and thecurve at right angles to this base r-Furthermore;should aflaw be found in any curve of a dioptric power'of 7.00; and the portion of the ring, the defective portion y opposite surface a spherical curve of 'apmay be cut out without destroying so much proximately 6.25'd1optric power, we have glass as would be necessary should any inwhat is known in the optical trade as planodividual lens be found defective under the cylinder toric +1.00 lens. The ring is then old system. I cleaned and inspected for flaws, focus and What I claim as my invention and desire 30 center. f a to secure by Letters Patent is Fromthis ring, segments are cut to pro- 1; A. blank suitable for forming a pluvide different individual lens blanks. 'Asr'ality of ophthalmic lenses comprising a 'sumi'ng for a pair of eyeglasses that the ring shaped member havinga surface curved right eye requires .-|-1.00 cylinder axis 90, concentrically with the center of the ring 35 'While the left eye requires +1.00 cylinder and also transversely of the plane of the axis 180' size-33x12 mm, the two lenses are ring. v

.cut from the ring blank in the manner 2. A blank suitable for forming a plushown in dotted llnes-in Fig. 8. Allowing rality of ophthalmic lenses comprising a 1 mm. for edging, it will be noted that from rlng shaped member having two surfaces one '40 the ring blank a-portion would be used or of which is convex and the other ofwhich out of the size 47x77 mm. Whereas under is concave, each surface being curved conthe "old method a surface f1 x94 mm. would centrically with the center of the ring and be requiredn1ak1ng a difference of 47x17 also transversely'of the plane of the ring. mmvsaved ora saving-of about 25% from I the ,same amount of developed .glass. HENRYC. MlELKE. I 

